Traditionally, a user interacts with a handheld device in a limited volume of space, usually on a display surface of the device. For example, a smart phone with a touch-sensitive display allows a user to interact with the device and the user interface in the volume of space immediately adjacent to the display screen. Limiting user interaction to an almost planar area that is between a user interface and the user limits the types of interactions available to the user and may introduce usability problems, such as occlusion of the user interface. Additionally, limiting an area of user interaction to a relatively two-dimensional scope prevents the user from manipulating objects presented in the user interface in a natural and intuitive manner.